[Mandatory mask ventilation before relaxation. Where is the evidence?].

Many anesthesia textbooks advise anesthesiologists to demonstrate that ventilation with a facemask is possible before giving muscle relaxants. This recommendation is not evidence-based. If a functional airway obstruction is responsible for difficult mask ventilation and with high induction doses it will rarely be possible for the patient to recover spontaneous ventilation before hypoxia develops. Muscle relaxants improve facemask ventilation and facilitate tracheal intubation. With early administration of muscle relaxants good intubation conditions are achieved earlier. The recommendation does not include a definition of successful mask ventilation and makes the decision in critical situations ambiguous. This is probably one of the reasons why most anesthesiologists administer muscle relaxants even though mask ventilation is difficult or impossible. Therefore the authors recommend giving muscle relaxants after loss of consciousness and thereafter starting gentle bag mask ventilation. To prevent a cannot ventilate cannot intubate situation patient airways have to be carefully evaluated preoperatively. If difficult ventilation or intubation is expected an alternative procedure should be chosen.